16 Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all,
*So, it's through belief that we receive God's grace. This ensures that the promise is certain for all of Abraham's descendants, not just those following the law, but also those who believe, like Abraham himself, who is the father of us all.